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20年来三代可记录光盘记录材料的研究概况 总被引:1,自引:0,他引:1
本文综述了近20年来应用于红外光CD-R、红光DVD±R和蓝光BD-R/HD DVD-R三代可记录光盘中的记录材料的研究和应用进展,介绍了菁类、大环氮杂、偶氮、金属螯合物、苯并杂环等类染料作为光记录材料进行的研究,评述了可记录光盘记录材料的薄膜光学、记录灵敏度、光热稳定性、旋涂成膜性等特性,概括了每一代可记录光盘记录材料的特性与光盘系统的关系,讨论了大环氮杂金属配合物具有的良好材料特性,尤其是高光热稳定性和适中的记录灵敏度,并结合大环氮杂金属配合物在早期两代可记录光盘中已得到的重要应用及本课题组对此类材料的研究结果,认为其将是高密度蓝光盘记录材料的重要发展方向之一. 相似文献
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由噻唑类偶氮染料和硝化纤维组成的复合材料涂布于玻璃载体上可用作光盘记录介质,测定这一记录介质的光学性质和物理性质,表明其具有良好的记录灵敏性和读写特性。 相似文献
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《化学通报》2000,63(10):55
北京宏剑科讯化学系统软件中心 ,全部面向 PC机平台 ,使您的家庭电脑也能完成工作站上的化学计算。我们为您提供了三十余个版本的化学软件 ,包括全世界最优秀的化学桌面系统软件 Chem Office2 0 0 0 ,Sci Vision和 Gaussian98W等系列软件包 ,适合业内教授、高级工程师及学生使用 ,使您的化学研究乘上互联网的世界快车。 Chem Office Ultra2 0 0 0 Enhanced集成化学软件桌面系统给化学家带来一个意想不到的惊奇 ,优秀的价格性能比 ,三位一体 (Chem Draw Ultra6 .0、Chem3D Ultra5 .0和 Chem Finder Ultra5 .1 )的功效以及强大的高端… 相似文献
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最近130ka中国的古季风——Ⅰ.古季风记录 总被引:24,自引:0,他引:24
现今中国季风气候的特点可以作为辨认古季风气候记录的线索。文中着重阐述最近130ka东南季风区的各种古季风记录,它们主要是:历史记录,包括黄土-古土壤序列、沙漠、湖泊、雪线和林线、大陆架沙漠化现象等的地质记录,由植被和哺乳动物代表的生物记录。其中,黄土高原的黄土-古土壤序列反映了过去亚洲冬季风和夏季风的环境效应突出气候期相互交替的历史。亚洲古季风变迁是中国古气候和古环境变迁的一个重要控制因素。 相似文献
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Mapping of the distribution of 137Cs in Irish Sea sediments 总被引:1,自引:0,他引:1
I. Osvath P. P. Povinec M. S. Baxter L. Huynh-Ngoc 《Journal of Radioanalytical and Nuclear Chemistry》2001,248(3):735-739
The Sellafield nuclear fuel reprocessing plant released a total of 41 PBq of 137Cs into the Irish Sea in the period 1952–1998. The present work integrates a series of surveys of the 137Cs distribution in sediment offshore Sellafield which was aimed at obtaining a detailed picture of the patterns of sediment contamination and their time evolution, and an estimate of the 137Cs inventory in sediment. The authors applied NaI(Tl)-based underwater -ray spectrometry to record a series of 1800 one-minute spectra along 14 transects totaling 160 Nm. The dominant feature of the contamination pattern obtained from this survey remains a stripe extending northwestwards along the coast from the discharge point, as reported for previous surveys. Steep gradients are observed perpendicular to the coast, with 137Cs countrates decreasing to half the recorded maximum over a distance of less than 2000 m. 相似文献
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A commercial FT-IR spectrometer (BRUKER IFS 66) was combined with a Raman module, having an NdYAG laser as source, a sample compartment, a filter for elimination of the exciting line from the spectrum and a detector. The interferometer and computer of the IFS 66 was used to record Raman spectra of small amounts of liquids and solids using a spherical sapphire sample cell. 相似文献
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以人教版高中化学必修模块教科书(2019年版)“实验”和“实验活动”栏目的实验活动为研究对象,采用Herron修正的“实验活动探究层次分类法”(LOLA)和笔者提出的“学生实验行为要求分类法”(RSBLA)对其进行分析,并与2007年版教科书进行对比。研究发现,2019年版教科书的实验活动探究层次处于层次1和层次2,学生行为要求为“观察”“记录实验现象”“回答与实验有关的问题”和“设计实验”。卡方检验表明,2019年版教科书和2007年版教科书“实验”栏目的实验活动探究层次分布比例和学生实验行为要求均存在显著性差异。 相似文献
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Network polymers near their gel point exhibit selfsimilar mechanical behavior, as expressed by power law relaxations. The range of selfsimilarity is defined by two limiting length scales. The upper limit is the correlation length, defined by the linear size of the typical cluster, and a lower limit, roughly given by the size of one preformed linear chain, i. e., the mean distance between crosslinks. The correlation length increases with the approach to the gel point, and diverges at the critical extent of reaction, i. e., the gel point where the infinite cluster is formed. Above the gel point, it decreases again with further crosslinking. Dynamic mechanical measurements of the complex modulus at the gel point show a power law in the frequency dependence over the entire frequency range, monitoring selfsimilarity. Swelling effects reduce the fractal dimension of the percolation cluster form 2.5 to 2. It is shown how the power law G()
1/2, found by experiment, is connected to the structure of the polymeric cluster.Presented at the Physikertagung 1987 in Berlin. 相似文献
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Bertini I Engelke F Luchinat C Parigi G Ravera E Rosa C Turano P 《Physical chemistry chemical physics : PCCP》2012,14(2):439-447
This perspective paper is intended to give some insights into the recently proposed technique of NMR of solutes sedimented by ultracentrifugation in a rotor used for solid state NMR experiments. Sedimented "states" correspond to molecules with very little reorientational capability in extremely concentrated solutions. They provide solid state NMR spectra comparable in quality with those of the best microcrystalline samples. Here we report some experiments to look for chemicals which affect the properties of the sediment, and we show that it is possible to fill the rotor in a true ultracentrifuge and then record the spectra. The latter possibility opens new horizons for NMR of sedimented systems. 相似文献
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Variations of radon in soils induced by external factors 总被引:1,自引:0,他引:1
N. Segovia J. L. Seidel M. Monnin 《Journal of Radioanalytical and Nuclear Chemistry》1987,119(3):199-209
Experiments were designed to evaluate, in a controlled way, some of the variations that can be expected in radon concentration in soil due mainly to meteorological factors and to close spacing monitoring in the field. Electronic continuous radon monitoring and the track-etch method were used to record the radon -decay. The radon emanation in daily measurements and in long term surveys showed a general effect modulated by temperature and pressure variations. Radon monitoring in soil for nearby stations showed that a 10% range of variation can be expected with the track-etch method and as a result of non-homogeneous emanation pattern of the soil. 相似文献
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Abstract An electromechanical effect arises in cholesteric (N*) liquid crystals due to a cross-coupling between fluxes and forces specific to chiral systems. We recently described an experiment to study this effect on samples with fixed boundary conditions. Here, we have derived the basic theoretical expressions relevant to this experiment. We have now used this technique to record the electromechanical signal across the compensation temperature of cholesteric mixtures consisting of cholesteryl chloride, 4′-heptyl-4-cyanobiphenyl and 2-cyano-4-heptylphenyl 4′-pentylbiphenyl-4-carboxylate. The sign of the electromechanical signal changes at the compensation point, clearly demonstrating the macroscopic origin of this effect. 相似文献